JP3797178B2

JP3797178B2 - Plastic molded product

Info

Publication number: JP3797178B2
Application number: JP2001305579A
Authority: JP
Inventors: 毅荒井; 広行柘植; 毅司村田; 義孝神谷; 勉尾上; 孝雄瀬木
Original assignee: Denso Corp
Current assignee: Denso Corp
Priority date: 2000-11-06
Filing date: 2001-10-01
Publication date: 2006-07-12
Anticipated expiration: 2021-10-01
Also published as: JP2002200643A

Description

【０００１】
【発明の属する技術分野】
本発明は、樹脂成形品に関し、特に１次成形で成形した一次成形品をインサートとして、更に成形樹脂で覆う２次成形により成形されたインサート成形品に関する。
【０００２】
【従来の技術】
従来より、複数のインサート部材を金型内にセットして成形樹脂によりインサート成形して一次成形品を得、その一次成形品をインサートして更に成形樹脂により成形し二次成形品を得ることが行われている。しかしながら、インサート部材と一次成形部、及び一次成形部と二次成形部との界面に僅かながら隙間が発生し、この隙間に水、空気、油等が侵入し、例えばインサート部材が金属端子である場合には、金属端子間の絶縁抵抗が低下する等の不都合があった。
【０００３】
そこでこのような気密性の問題を解決する従来技術として、特開平９−３００４０１号公報により提案されたインサート成形品の成形方法が公知である。このインサート成形品１０の成形方法は、図５と図６に示されるように、インサート部材１と一次成形部２との気密は、インサート部材１にシール剤４（例えばヒドリン系ゴム）を塗布することで実施し、一次成形部２と二次成形部３との気密は、一次成形部２に突起部２Ａを形成し、二次成形時に溶融している成形樹脂の熱によりこの突起部２Ａを溶かし、一次成形部２を二次成形部３に溶着させることでインサート成形品１０の気密性を得ているものである。
【０００４】
しかしながら、この場合における一次成形部２と二次成形部３の溶着部が中央に配置されているのに対して、二次成形時の成形樹脂のゲート位置は構造上中央に配置することができず、樹脂流れを均一にできない。このため溶着部にかかる樹脂の温度、圧力が場所によって異なり、特にゲート位置の反対側の温度の低い所では、一次成形部２の突起部２Ａが二次成形部３に溶着しないことがあり、良好な気密性を達成することができなかった。
【０００５】
【発明が解決しようとする課題】
本発明の目的は、上記の問題に鑑み、インサート部材と一次成形部、及び一次成形部と二次成形部の気密性を高めた樹脂成形品を提供することである。
【０００６】
【課題を解決するための手段】
本発明は、前記課題を解決するための手段として、特許請求の範囲の各請求項に記載の樹脂成形品を提供する。
請求項１に記載の樹脂成形品は、一次と二次の成形部とからなる樹脂成形品であって、二次成形部を形成する二次成形樹脂の流れ方向に対して、一次成形部の外周に第１の環状突起を設けると共に、この環状突起の樹脂流れ上流側で二次成形樹脂の流路を絞る絞り部とを設けたものであり、この絞り部によって二次成形樹脂の整流を行い、二次成形樹脂が第１の環状突起に到達するタイミングを均一化している。したがって、突起全周で均等な溶着状態を発生させることで安定したシール性が得られる。
【０００７】
請求項２の樹脂成形品は、絞り部を一次成形部に更に設けた第２の環状突起に規定したものである。
【０００８】
請求項３の樹脂成形品は、絞り部を、二次成形部の一部の厚さを他の部位よりも薄くすることによって構成することを規定したものである。
【０００９】
請求項４の樹脂成形品は、絞り部における二次成形部の厚さが、絞り部と第１の環状突起との間隔よりも短いことを規定したものであり、二次成形樹脂が均一に第１の環状突起に到達する条件を提示している。
【００１０】
請求項５の樹脂成形品は、第１の環状突起によって形成される二次成形部の薄肉部よりも樹脂流れ下流側の二次成形部が、少なくともこの薄肉部よりも厚い樹脂厚を有し、かつその長さがこの薄肉部の厚さの３倍以上に設定したものであり、これによって、二次成形樹脂から第１の環状突起に十分な熱量が与えられ、突起の溶融が十分に行われて一次成形部と二次成形部との密着性を向上できる。
【００１１】
【発明の実施の形態】
以下に図面を参照して本発明の実施の形態のインサート成形品について説明する。図１は、本発明のインサート成形品の一次成形の段階における一次成形品の（ａ）平面図と、（ｂ）縦断面図であり、図２は、二次成形が終了した本発明のインサート成形品の縦断面図である。
本発明のインサート成形品１０は、インサート部材１、一次成形部２及び二次成形部３とから構成されている。なお、図１（ｂ）において符号５は一次成形時に成形樹脂が注入されるゲートを示しており、図２の符号６は、二次成形時に成形樹脂が注入されるゲートを示している。
【００１２】
この一次成形部２には、第１の凸部（厚肉部）２ａと、一次成形時に成形樹脂の流れを均一化させるための第１の凹部（薄肉部）２ｂと、第２の凸部（厚肉部）２ａ’と、一次成形時にインサート部材１と一次成形部との気密性を高めるために、気密性を要する部分のインサート部材１の全周に設けた第２の凹部（薄肉部）２ｂ’及び整流化の為の第１の凹部２ｂ以降の凸部に設けた突起部７とが設けられる。したがって、前記突起部を除いては、一次成形部２は、凸部と凹部が交互に少なくとも２組設けられ、その外側面形状が凹凸状となっている。ここで、インサート部材の長さ方向における上記凸部（厚肉部）２ａ，２ａ’の長さ（高さ）ｔ₁ ，ｔ₃ と、上記凹部（薄肉部）２ｂ，２ｂ’の厚さｔ₂ とは、ｔ₁ ＞ｔ₂ ，ｔ₃ ＞ｔ₂ の関係が満足されるように設定されている。さらに、第２の凹部２ｂ’の樹脂流れ下流側には、さらに凸部２ｃが設けられており、この凸部２ｃの長さｔ₄ も、凹部２ｂ，２ｂ’の厚さｔ₂ よりも大きく設定されている（ｔ₄ ＞ｔ₂ ）。
【００１３】
これに対して二次成形部３は、その外側面形状がインサート部材１と平行で、ほぼ平坦状となっている。また二次成形部３の内側面形状は、一次成形部の整流化の為の凸部以降の凸部に設けた突出部を除いては、一次成形部の凹凸状の外側面形状に噛み合う形で同じく凹凸状となっている。即ち、一次成形部２の第１の凸部２ａに対応して二次成形部３では第１の凹部（薄肉部）３ｂが形成される。この第１の凹部３ｂを通過する時に二次成形樹脂の樹脂流れが均一化される。この第１の凹部３ｂの樹脂流れ上流側には、第１の凸部３ａが形成され、ゲート６から注入された二次成形樹脂は、まずこの第１の凸部３ａに充填される。さらに一次成形部２の第１の凹部２ｂに対応して二次成形部３では第２の凸部（厚肉部）３ａ’が形成され、同様に一次成形部２の第２の凸部２ａ’及び凸部上の突起部７に対して二次成形部３では第２の凹部（薄肉部）３ｂ’が、一次成形部２の第２の凹部２ｂ’に対して二次成形部３では第３の凸部（厚肉部）３ａ''がそれぞれ形成される。第３の凸部３ａ''の下流側には、第３の凹部３ｂ''がさらに形成される。
また、二次成形部３においても、凸部３ａ，３ａ’，３ａ''の長さ（高さ）ｔ₇ ，ｔ₈ ，ｔ₉ と凹部３ｂ，３ｂ’，３ｂ''の厚さｔ₅ とは、ｔ₇ ＞ｔ₅ ，ｔ₈ ＞ｔ₅ ，ｔ₉ ＞ｔ₅ の関係が満足されるように設定されている。
これにより凹部３ｂ，３ｂ’，３ｂ''における二次成形樹脂の流動抵抗が高められ、第１の凹部３ｂによる整流効果、及び第２の凹部３ｂ’における圧力上昇による密着性の向上効果を得ることができる。
また、凹部３ｂ，３ｂ’，３ｂ''において流動抵抗が高くなるように、ゲート６から第１の凸部３ａまでの樹脂厚さｔ₆ も凹部３ｂ，３ｂ’，３ｂ''の厚さｔ₅ よりも厚くされている（ｔ₆ ＞ｔ₅ ）。
さらに、加熱された二次成形樹脂が、第２の凹部３ｂ’を流動して一次成形部の外周に形成された突起部７を溶融できるように、第３の凹部３ｂ''の下流側の第４の凸部３ａ''' の長さｔ₁₀がｔ₁₀／ｔ₅ ＞３の関係を満足する。
このように、本発明の実施の形態のインサート成形品では、一次成形部２及び二次成形部３に２ケ所以上の外周全周に渡る凹部（薄肉部）、及び２ケ所以上の外周全周に渡る凸部（厚肉部）を作ることで、気密性を高めることを可能としている。
【００１４】
図１では、インサート部材１の横断面形状が矩形状で示されているが、円形でも或いは多角形でも同様に行い得るものである。
【００１５】
次に、図１を参照して一次成形について詳細に説明する。
インサート部材１と一次成形部２との界面では、一次成形のゲート５から射出された溶融樹脂は、一次成形時、前述のｔ₁ ＞ｔ₂ の関係から該第１の凹部（薄肉部）２ｂに溶融樹脂が流れ込む前に、第１の凸部（厚肉部）２ａを有する肉厚の厚い全周方向に樹脂が充填され、その後、第１の凹部２ｂである薄肉部に樹脂が充填される。これにより、第１の凹部２ｂによって一次成形樹脂の樹脂流れが均一化される。次に、一次成形樹脂は第２の凸部２ａ’及び凸部２ａ’に設けた溶着用（二次成形時）の突起部７を経て、一次成形部２の気密性を要する部分の全周に設けた第２の凹部（薄肉部）２ｂ’に流れ込む。このため、第１の凹部２ｂにおいて、樹脂の流れが均一化されているため、第２の凹部２ｂ’では樹脂流れが均一になり、気密性（密着性）に偏りが出ず、全体としての気密性が強くなる。また、一次成形部２の気密性を要する部分の全周に設けた第２の凹部２ｂ’が薄肉であることから、樹脂圧力が大きくなり、転写性が向上する。従って、インサート部材１と一次成形部２との気密性は向上する。
【００１６】
インサート部材１にシール剤４を塗布した場合においては、一次成形部２の気密性を要する部分の全周に設けた第２の凹部２ｂ’が薄肉であることから、圧力、せん断発熱が大きくなり、シール剤４がよく圧縮されること、及び熱と圧力とによりシール剤４がよく反応すること等により、インサート部材１と一次成形部２の気密性（密着性）が一層向上する。
【００１７】
次に、図２を参照して二次成形について説明する。
一次成形部２と二次成形部３との界面では、二次成形のゲート６から射出された溶融樹脂は、まず二次成形時、樹脂流れを均一化させるために設けた二次成形部３の第１の凹部３ｂである薄肉部に樹脂が流れ込む前に、第１の凸部３ａに樹脂が充填される。その後、この第１の凹部（薄肉部）３ｂに樹脂が充填される。これにより、第１の凹部３ｂを通過する樹脂流れが均一化される。次に、二次成形樹脂は、第２の凸部３ａ’を経て、気密性を高めるために設けた二次成形部３の第２の凹部（薄肉部）３ｂ’に流れ込む。したがって、二次成形時、二次成形部３の第１の凹部３ｂの薄肉部で樹脂流れが均一化されるので、気密性を要する部分である二次成形部３の第２の凹部３ｂ’の薄肉部での樹脂流れも均一になり、気密性に偏りが出ず、全体としての気密性が強くなる。また、気密性を要する部分自体が薄肉であることから、圧力、せん断発熱が大きくなり、二次成形時、気密性を高めるために一次成形部の気密性を要する部分の全周に設けた第２の凸部（厚肉部）２ａ’上に設けた突起部７の溶融度が大きくなるため、第２の凸部２ａ’の二次成形部３への溶着率が大きくなる。したがって、一次成形部２と二次成形部３の気密性（密着性）は向上する。
なお、突起部７を設けなくとも、二次成形樹脂は一次成形部２の第２の凸部２ａ’の先端部を溶融するため、二次成形部３は一次成形部２に溶着される。しかしながら、一次成形部２の第２の凸部２ａ’に突起部７を設けることにより、熱容量を小さくできるので、溶融度を大きくすることができ、より確実に二次成形部３と一次成形部２とを溶着することができる。
【００１８】
なお、本発明に用いられる成形樹脂としては、オレフィン系樹脂、塩化ビニル樹脂、ポリエステル樹脂、ポリアミド樹脂、ＡＢＳ樹脂、ポリカーボネート樹脂、アセタール樹脂、ふっ素樹脂等の一般的な熱可塑性樹脂を用いることができ、一次成形と二次成形とで成形樹脂を変えることもできる。これらの樹脂は、通常の方法にしたがって、安定剤、帯電防止剤、難燃剤、可塑剤、補強剤等の添加剤を含んでもよい。またインサート部材は、金属、セラミックス等適宜の材料を使用することができ、その大きさ、形状も特に制限されないものである。
【００１９】
また、インサート部材１、一次成形部２及び二次成形部３の形状も、上述の例に限定されず種々変更可能である。例えば、インサート部材１として中心軸の側面に凹凸（一次成形部の整流化の為の凸部以降の凸部外周に設けた突起部を除く）が設けられる場合、このインサート部材の凹凸形状に合わせて一次成形部２の内断面形状が凹凸状に形成される。この場合の一次成形部２の外側面形状は平坦でも凹凸状でも良い。一次成形部２の外側面形状が平坦である場合には、二次成形部３の外側面形状に凹凸を設ければ、前述のように、一次成形品の周囲に少なくとも２組の凸部及び凹部を有する二次成形部を形成することができる。
また、一次成形樹脂と二次成形樹脂とは、同じ樹脂材料であって良いし、異なる樹脂材料であっても良い。
【００２０】
図３，４は、本発明の別の実施の形態に係るものであり、一次成形部２と二次成形部３との密着性、気密性の向上に焦点をあてたものであり、先の実施の形態のように一次成形部２とインサート部材１との関係については特に問題としていないものである。（インサート部材は有っても無くてもよい。）
図３における実施例における樹脂成形品では、一次成形部２の外周表面に第１の環状突起Ｂを形成すると共に、この第１の環状突起Ｂの二次成形樹脂流れ上流側において、この二次成形樹脂の流路を絞る絞り部Ｄを設けている。図３の実施例では、この絞り部Ｄが、一次成形部２の外周表面に設けた第２の環状突起Ａにより形成されている。図４の実施例では、この絞り部Ｄが、二次成形部３の一部Ａの厚さを他の部位よりも薄くすることによって形成されている。
【００２１】
また、二次成形部３の絞り部Ｄの厚さ（Ｄ）が、絞り部と第１の環状突起Ｂとの間隔（Ｅ）よりも短いことが好ましい。更に、第１の環状突起Ｂによって形成される二次成形部３の薄肉部Ｃよりも樹脂流れ下流側の二次成形部３は、少なくともこの薄肉部Ｃよりも厚い樹脂厚を有していて、かつその長さ（Ｆ）が、この薄肉部の厚さ（Ｃ）の３倍以上に設定することが好ましい。
これにより、二次成形時に、絞り部Ｄで二次成形樹脂の整流が行われ、二次成形樹脂が一次成形部２の第１の環状突起Ｂに到達するタイミングを、環状突起Ｂの全周に渡って均一化することができる。従って、二次成形樹脂の熱により環状突起Ｂの先端部はほぼ同時期に溶融されるため、この環状突起Ｂの全周における二次成形樹脂への溶着状態の均等化を図ることができて、安定したシール性を得ることができる。
なお、第１の環状突起Ｂの後段の２つの比較的大型の突起は、一次成形部２の外周に間欠的に形成された回り止めである。
【００２２】
図２〜図４に示される本発明の実施形態において、インサート部材１や一次成形部２は１つに限られるものではない。例えば、２つあるいは３つ以上のインサート部材を一次成形部２にインサート成形しても良いし、別個に成形された複数の一次成形部を組み合わせたものを二次成形樹脂によって二次インサート成形しても良い。
図２に示す実施の形態では、二次成形部３に厚肉部と薄肉部とからなる凹凸部を３対設け、その２対目の薄肉部３ｂ’に対応する一次成形部２の厚肉部２ａ’に突起部７を設けていた。
しかしながら、突起部７は、３対目の薄肉部３ｂ''に対応する、一次成形部２の厚肉部２ａ''に設けても良い。このようにすると、一対目及び二対目の厚肉部３ａ，３ａ’と薄肉部３ｂ，３ｂ’とで、二次成形樹脂の整流効果を高めることができる。この結果、二次成形樹脂が突起部７に到達するタイミングを、その突起部７の全周に渡って正確に揃えることができるので、突起部７の全体で均一な溶着を行うことができる。
さらに、図３、図４に示す実施の形態においても、一次成形部２の外周表面に形成される環状突起Ｂの二次成形樹脂の流れ方向の上流側に、１つの絞り部Ｄのみではなく、２つ以上の絞り部を設けても良い。
【００２３】
以上説明したように、本発明のインサート成形品においては、インサート部材と一次成形部、および／または、一次成形部と二次成形部との気密性（密着性）が向上でき、これらの界面からの水、空気、油等の侵入もしくは漏出を防止でき、例えば絶縁抵抗の低下を防止できる。
【図面の簡単な説明】
【図１】本発明の実施の形態のインサート成形品の一次成形の段階での一次成形品の、（ａ）平面図と、（ｂ）縦断面図とである。
【図２】二次成形が終了した本発明の実施の形態のインサート成形品の縦断面図である。
【図３】本発明の別の実施の形態の樹脂成形品の断面図及び部分拡大断面図である。
【図４】本発明の更に別の実施の形態の樹脂成形品の断面図及び部分拡大断面図である。
【図５】従来のインサート成形品の一次成形の段階での一次成形品の斜視図である。
【図６】従来の二次成形が終了したインサート成形品の縦断面図である。
【符号の説明】
１…インサート部材
２…一次成形部
３…二次成形部
４…シール剤
５…一次成形時のゲート
６…二次成形時のゲート
７…溶着用（二次成形時）突起部
１０…インサート成形品
Ａ…第２の環状突起
Ｂ…第１の環状突起
Ｃ…薄肉部（二次成形部材）
Ｄ…絞り部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a resin molded product, and more particularly to an insert molded product molded by secondary molding covered with a molded resin using a primary molded product molded by primary molding as an insert.
[0002]
[Prior art]
Conventionally, it is possible to set a plurality of insert members in a mold and insert-mold with a molding resin to obtain a primary molded product, insert the primary molded product and further mold with a molding resin to obtain a secondary molded product. Has been done. However, a slight gap is generated at the interface between the insert member and the primary molded portion, and between the primary molded portion and the secondary molded portion, and water, air, oil, etc. enter the gap, for example, the insert member is a metal terminal. In such a case, there is a disadvantage that the insulation resistance between the metal terminals is lowered.
[0003]
Therefore, as a conventional technique for solving such a problem of airtightness, a method for forming an insert-molded product proposed by JP-A-9-300401 is known. In the molding method of the insert molded product 10, as shown in FIGS. 5 and 6, the sealing material 4 (for example, hydrin rubber) is applied to the insert member 1 for airtightness between the insert member 1 and the primary molded portion 2. The airtightness between the primary molded part 2 and the secondary molded part 3 is achieved by forming the protruding part 2A in the primary molded part 2 and by using the heat of the molding resin melted during the secondary molding. The airtightness of the insert molded product 10 is obtained by melting and welding the primary molded part 2 to the secondary molded part 3.
[0004]
However, in this case, the welded portion of the primary molding portion 2 and the secondary molding portion 3 is arranged in the center, whereas the gate position of the molding resin at the time of secondary molding can be arranged in the center in terms of structure. Therefore, the resin flow cannot be made uniform. For this reason, the temperature and pressure of the resin applied to the welded portion vary depending on the location, and the projection 2A of the primary molded portion 2 may not be welded to the secondary molded portion 3 particularly at a low temperature on the opposite side of the gate position. Good airtightness could not be achieved.
[0005]
[Problems to be solved by the invention]
In view of the above problems, an object of the present invention is to provide a resin molded product in which the insert member and the primary molded portion, and the airtightness of the primary molded portion and the secondary molded portion are improved.
[0006]
[Means for Solving the Problems]
The present invention provides a resin molded product according to each of the claims as means for solving the above-mentioned problems.
The resin molded product according to claim 1 is a resin molded product composed of a primary molded part and a secondary molded part, and the primary molded part is in the flow direction of the secondary molded resin forming the secondary molded part. A first annular protrusion is provided on the outer periphery, and a throttle part for restricting the flow path of the secondary molding resin is provided on the upstream side of the resin flow of the annular protrusion, and the secondary molding resin is rectified by the throttle part. The timing at which the secondary molding resin reaches the first annular protrusion is made uniform. Therefore, a stable sealing property can be obtained by generating a uniform welding state around the entire protrusion.
[0007]
The resin molded product according to the second aspect is defined by a second annular projection in which a throttle portion is further provided in the primary molding portion.
[0008]
The resin molded product according to claim 3 stipulates that the narrowed portion is configured by making a part of the secondary molded portion thinner than other portions.
[0009]
The resin molded product according to claim 4 stipulates that the thickness of the secondary molded portion in the drawn portion is shorter than the distance between the drawn portion and the first annular protrusion, and the secondary molded resin is uniform. Conditions for reaching the first annular protrusion are presented.
[0010]
The resin molded product according to claim 5 is such that the secondary molded portion on the downstream side of the resin flow is at least thicker than the thin portion of the secondary molded portion formed by the first annular protrusion. In addition, the length is set to be three times or more the thickness of the thin wall portion, whereby a sufficient amount of heat is given from the secondary molding resin to the first annular protrusion, and the protrusion is sufficiently melted. As a result, the adhesion between the primary molded part and the secondary molded part can be improved.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an insert molded product according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1A is a plan view of a primary molded product at the stage of primary molding of the insert molded product of the present invention, and FIG. 1B is a longitudinal sectional view thereof. FIG. 2 is an insert of the present invention after secondary molding is completed. It is a longitudinal cross-sectional view of a molded article.
The insert molded product 10 of the present invention includes an insert member 1, a primary molded portion 2, and a secondary molded portion 3. In FIG. 1B, reference numeral 5 denotes a gate into which molding resin is injected during primary molding, and reference numeral 6 in FIG. 2 denotes a gate into which molding resin is injected during secondary molding.
[0012]
The primary molding part 2 includes a first convex part (thick part) 2a, a first concave part (thin part) 2b for making the flow of molding resin uniform during primary molding, and a second convex part. (Thick part) 2a ′ and a second recess (thin part) provided on the entire circumference of the insert member 1 in a portion requiring airtightness in order to improve the airtightness between the insert member 1 and the primary molded part at the time of primary molding. ) 2b ′ and the protrusion 7 provided on the convex part after the first concave part 2b for rectification. Therefore, except for the protrusions, the primary molded part 2 is provided with at least two pairs of convex parts and concave parts alternately, and the outer surface shape thereof is uneven. Here, the lengths (heights) t ₁ and t _{3 of the} convex portions (thick portions) 2a and 2a ′ in the length direction of the insert member and the thickness t of the concave portions (thin portions) 2b and 2b ′. ₂ is set so that the relationship of t ₁ > t ₂ and t ₃ > t ₂ is satisfied. Further, a convex portion 2c is further provided on the resin flow downstream side of the second concave portion 2b ′, and the length t ₄ of the convex portion 2c is also larger than the thickness t ₂ of the concave portions 2b and 2b ′. It is set (t ₄ > t ₂ ).
[0013]
On the other hand, the secondary molded portion 3 has an outer surface shape that is parallel to the insert member 1 and is substantially flat. Further, the shape of the inner side surface of the secondary molded portion 3 is a shape that meshes with the concave and convex outer surface shape of the primary molded portion except for the protruding portion provided on the convex portion after the convex portion for rectification of the primary molded portion. It is also uneven. That is, the first concave portion (thin wall portion) 3 b is formed in the secondary molding portion 3 corresponding to the first convex portion 2 a of the primary molding portion 2. The resin flow of the secondary molding resin is made uniform when passing through the first recess 3b. A first convex portion 3a is formed on the upstream side of the resin flow of the first concave portion 3b, and the secondary molding resin injected from the gate 6 is first filled into the first convex portion 3a. Furthermore, a second convex portion (thick portion) 3a ′ is formed in the secondary molded portion 3 corresponding to the first concave portion 2b of the primary molded portion 2, and the second convex portion 2a of the primary molded portion 2 is similarly formed. The second concave portion (thin wall portion) 3b 'in the secondary molded portion 3 with respect to the projection 7 on the convex portion and the secondary molded portion 3 in the second concave portion 2b' of the primary molded portion 2 Third convex portions (thick portions) 3a '' are formed. A third recess 3b '' is further formed on the downstream side of the third protrusion 3a ''.
Also in the secondary molded part 3, the lengths (heights) t ₇ , t ₈ , t _{9 of} the convex parts 3a, 3a ′, 3a ″ and the thickness t _{5 of} the concave parts 3b, 3b ′, 3b ″. Is set so that the relations t ₇ > t ₅ , t ₈ > t ₅ , t ₉ > t ₅ are satisfied.
As a result, the flow resistance of the secondary molding resin in the recesses 3b, 3b ′, 3b ″ is increased, and a rectifying effect by the first recess 3b and an effect of improving adhesion due to a pressure increase in the second recess 3b ′ are obtained. be able to.
Further, the resin thickness t ₆ from the gate 6 to the first convex portion 3a is also the thickness t of the concave portions 3b, 3b ′, 3b ″ so that the flow resistance becomes high in the concave portions 3b, 3b ′, 3b ″. _It is thicker than ₅ (t ₆ > t ₅ ).
Further, the heated secondary molding resin flows in the second concave portion 3b ′ and melts the protrusion 7 formed on the outer periphery of the primary molded portion, so that the downstream side of the third concave portion 3b ″ can be melted. The length t _{10 of} the fourth convex portion 3a ′ ″ satisfies the relationship of t ₁₀ / t ₅ > 3.
As described above, in the insert molded product according to the embodiment of the present invention, the primary molded portion 2 and the secondary molded portion 3 have two or more outer circumferential perimeters (thin wall portions) and two or more outer circumferential circumferences. By making a convex part (thick part) that spans, it is possible to enhance the airtightness.
[0014]
In FIG. 1, the cross-sectional shape of the insert member 1 is shown as a rectangular shape, but it can be similarly performed in a circular shape or a polygonal shape.
[0015]
Next, the primary molding will be described in detail with reference to FIG.
At the interface between the insert member 1 and the primary molding portion 2, the molten resin injected from the primary molding gate 5 is subjected to the first concave portion (thin wall portion) 2b in the primary molding because of the relationship of t ₁ > t ₂ described above. Before the molten resin flows into the resin, the resin is filled in the thick circumferential direction having the first convex portion (thick portion) 2a, and then the thin portion which is the first concave portion 2b is filled with the resin. The Thereby, the resin flow of primary molding resin is equalized by the 1st crevice 2b. Next, the primary molding resin passes through the second projection 2a ′ and the projection 7 for welding (secondary molding) provided on the projection 2a ′, and then the entire circumference of the portion requiring the airtightness of the primary molding 2 Flows into the second concave portion (thin wall portion) 2b ′ provided in FIG. For this reason, since the resin flow is made uniform in the first recess 2b, the resin flow becomes uniform in the second recess 2b ′, and the airtightness (adhesion) is not biased. Airtightness becomes stronger. In addition, since the second concave portion 2b ′ provided on the entire circumference of the portion requiring the airtightness of the primary molding portion 2 is thin, the resin pressure is increased and the transferability is improved. Therefore, the airtightness between the insert member 1 and the primary molded portion 2 is improved.
[0016]
When the sealant 4 is applied to the insert member 1, the pressure and shear heat generation increase because the second recess 2 b ′ provided on the entire circumference of the portion requiring the airtightness of the primary molding portion 2 is thin. The airtightness (adhesiveness) between the insert member 1 and the primary molded part 2 is further improved by the fact that the sealant 4 is well compressed and the sealant 4 reacts well with heat and pressure.
[0017]
Next, secondary molding will be described with reference to FIG.
At the interface between the primary molding portion 2 and the secondary molding portion 3, the molten resin injected from the secondary molding gate 6 is first provided in order to make the resin flow uniform during the secondary molding. Before the resin flows into the thin portion which is the first concave portion 3b, the first convex portion 3a is filled with the resin. Thereafter, the first recess (thin wall portion) 3b is filled with resin. Thereby, the resin flow which passes the 1st recessed part 3b is equalized. Next, the secondary molding resin flows into the second concave portion (thin wall portion) 3b ′ of the secondary molding portion 3 provided to improve the airtightness through the second convex portion 3a ′. Therefore, at the time of secondary molding, the resin flow is made uniform in the thin portion of the first concave portion 3b of the secondary molded portion 3, so that the second concave portion 3b ′ of the secondary molded portion 3 which is a portion requiring airtightness. The resin flow at the thin wall portion becomes uniform, the airtightness is not biased, and the airtightness as a whole becomes strong. In addition, since the part requiring airtightness itself is thin, the pressure and shear heat generation are increased, and in the secondary molding, the first part provided on the entire circumference of the part requiring airtightness of the primary molded part in order to improve the airtightness. Since the degree of melting of the protrusion 7 provided on the second convex portion (thick portion) 2a ′ increases, the welding rate of the second convex portion 2a ′ to the secondary molded portion 3 increases. Therefore, the airtightness (adhesiveness) of the primary molding part 2 and the secondary molding part 3 improves.
Even if the protrusion 7 is not provided, the secondary molding resin melts the tip of the second convex portion 2 a ′ of the primary molding portion 2, so that the secondary molding portion 3 is welded to the primary molding portion 2. However, since the heat capacity can be reduced by providing the projection 7 on the second convex portion 2a ′ of the primary molding portion 2, the degree of melting can be increased, and the secondary molding portion 3 and the primary molding portion can be more reliably performed. 2 can be welded together.
[0018]
As the molding resin used in the present invention, a general thermoplastic resin such as an olefin resin, vinyl chloride resin, polyester resin, polyamide resin, ABS resin, polycarbonate resin, acetal resin, or fluorine resin can be used. The molding resin can be changed between primary molding and secondary molding. These resins may contain additives such as a stabilizer, an antistatic agent, a flame retardant, a plasticizer, and a reinforcing agent according to a usual method. In addition, an appropriate material such as metal or ceramics can be used for the insert member, and its size and shape are not particularly limited.
[0019]
Moreover, the shape of the insert member 1, the primary molding part 2, and the secondary molding part 3 is not limited to the above-mentioned example, but can be variously changed. For example, when the insert member 1 is provided with unevenness on the side surface of the central axis (excluding protrusions provided on the outer periphery of the convex part after the convex part for rectification of the primary molding part), it is matched with the concave and convex shape of this insert member. Thus, the inner cross-sectional shape of the primary molded portion 2 is formed in an uneven shape. In this case, the outer surface shape of the primary molded part 2 may be flat or uneven. When the outer surface shape of the primary molded part 2 is flat, if the outer surface shape of the secondary molded part 3 is uneven, as described above, at least two pairs of convex parts and around the primary molded product, A secondary molded part having a recess can be formed.
Further, the primary molding resin and the secondary molding resin may be the same resin material or different resin materials.
[0020]
3 and 4 relate to another embodiment of the present invention, focusing on the improvement of the adhesion and airtightness between the primary molded part 2 and the secondary molded part 3. As in the embodiment, the relationship between the primary molded portion 2 and the insert member 1 is not particularly a problem. (The insert member may or may not be present.)
In the resin molded product in the embodiment in FIG. 3, the first annular protrusion B is formed on the outer peripheral surface of the primary molded portion 2, and the secondary molded resin flow upstream of the first annular protrusion B A restricting portion D for restricting the flow path of the molding resin is provided. In the embodiment of FIG. 3, the narrowed portion D is formed by a second annular protrusion A provided on the outer peripheral surface of the primary molding portion 2. In the embodiment of FIG. 4, the narrowed portion D is formed by making the thickness of a part A of the secondary molded portion 3 thinner than other portions.
[0021]
Moreover, it is preferable that the thickness (D) of the narrowed portion D of the secondary molding portion 3 is shorter than the distance (E) between the narrowed portion and the first annular protrusion B. Further, the secondary molding portion 3 on the downstream side of the resin flow from the thin portion C of the secondary molding portion 3 formed by the first annular protrusion B has a resin thickness that is at least thicker than the thin portion C. And the length (F) is preferably set to 3 times or more the thickness (C) of the thin portion.
Thereby, at the time of secondary molding, rectification of the secondary molding resin is performed at the narrowed portion D, and the timing at which the secondary molding resin reaches the first annular projection B of the primary molding portion 2 is set to the entire circumference of the annular projection B. Can be made uniform over the entire area. Accordingly, the tip of the annular projection B is melted almost simultaneously by the heat of the secondary molding resin, so that it is possible to equalize the welding state to the secondary molding resin on the entire circumference of the annular projection B. Stable sealability can be obtained.
The two relatively large protrusions following the first annular protrusion B are detents that are intermittently formed on the outer periphery of the primary molding portion 2.
[0022]
In the embodiment of the present invention shown in FIGS. 2 to 4, the insert member 1 and the primary molded portion 2 are not limited to one. For example, two or three or more insert members may be insert-molded in the primary molding part 2 or a combination of a plurality of separately molded primary molding parts is subjected to secondary insert molding with a secondary molding resin. May be.
In the embodiment shown in FIG. 2, three pairs of uneven portions composed of a thick portion and a thin portion are provided in the secondary molded portion 3, and the thick portion of the primary molded portion 2 corresponding to the second pair of thin portions 3 b ′ is provided. The protrusion 7 was provided in the part 2a ′.
However, the protrusion 7 may be provided on the thick portion 2a '' of the primary molded portion 2 corresponding to the third pair of thin portions 3b ''. If it does in this way, the rectification | straightening effect of secondary molding resin can be heightened by the thick part 3a, 3a 'and thin part 3b, 3b' of the 1st and 2nd pair. As a result, the timing at which the secondary molding resin reaches the protruding portion 7 can be accurately aligned over the entire circumference of the protruding portion 7, so that uniform welding can be performed on the entire protruding portion 7.
Further, in the embodiment shown in FIGS. 3 and 4, not only the narrowed portion D is provided on the upstream side in the flow direction of the secondary molding resin of the annular projection B formed on the outer peripheral surface of the primary molded portion 2. Two or more apertures may be provided.
[0023]
As described above, in the insert molded product of the present invention, the airtightness (adhesion) between the insert member and the primary molded portion and / or the primary molded portion and the secondary molded portion can be improved, and from these interfaces Intrusion or leakage of water, air, oil, etc. can be prevented, for example, a decrease in insulation resistance can be prevented.
[Brief description of the drawings]
1A is a plan view and FIG. 1B is a longitudinal sectional view of a primary molded product in a primary molding stage of an insert molded product according to an embodiment of the present invention.
FIG. 2 is a longitudinal sectional view of an insert-molded product according to an embodiment of the present invention after secondary molding is completed.
FIG. 3 is a cross-sectional view and a partially enlarged cross-sectional view of a resin molded product according to another embodiment of the present invention.
FIG. 4 is a cross-sectional view and a partially enlarged cross-sectional view of a resin molded product according to still another embodiment of the present invention.
FIG. 5 is a perspective view of a primary molded product at a stage of primary molding of a conventional insert molded product.
FIG. 6 is a longitudinal sectional view of an insert-molded product after conventional secondary molding.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Insert member 2 ... Primary molding part 3 ... Secondary molding part 4 ... Sealing agent 5 ... Gate 6 at the time of primary molding ... Gate 7 at the time of secondary molding ... Welding (at the time of secondary molding) Projection part 10 ... Insert molding Product A ... second annular projection B ... first annular projection C ... thin part (secondary molding member)
D: Aperture part

Claims

A resin molded product comprising a primary molded part and a secondary molded part formed around the primary molded part,
A first annular projection is provided on the outer periphery of the primary molding portion with respect to the flow direction of the secondary molding resin forming the secondary molding portion, and the secondary molding resin is formed upstream of the resin flow of the annular projection. And a throttle part for restricting the flow path,
A resin molded product characterized in that the secondary molding resin is rectified by the narrowed portion so that the timing at which the secondary molding resin reaches the annular protrusion is made uniform.

The diaphragm unit according to claim 1, wherein the resin molded article characterized by being constituted by providing the second annular projection on the primary molding section.

The diaphragm unit according to claim 1, wherein the resin molded article characterized by being constituted by thinner than a portion of the thickness of the other portion of the secondary molding unit.

The thickness of the secondary molded portion in the aperture portion, resin molding according to any one of claims 1 to 3, characterized in that shorter than the distance between said first annular projection and the throttle portion Goods.

The secondary molded portion downstream of the resin flow from the thin portion of the secondary molded portion formed by the first annular projection has a resin thickness that is at least thicker than the thin portion, and the length thereof is The resin molded product according to any one of claims 1 to 4 , wherein the resin molded product is set to be three times or more the thickness of the thin portion.